Path of Exile: Sacrifice of the Vaal's Fifth Teaser Screenshot Features an Invasion

Are you sick of all the Path of Exile: Sacrifice of the Vaal teasers yet? Path of Exile's first mini-expansion is one week away, but developer Grinding Gear is apparently still keeping the details close to the chest. With the previous teaser screenshot coming from one of the new Challenge Leagues, Ambush, I guess it's only right that the other new Challenge League, Invasion, gets one as well.

As the name implies, it seems like there is some sort of scarab invasion occurring in the screenshot. Whereas each Act typically featured its own roster of enemies, when it comes to the Invasion Challenge League, it seems like enemies can "invade" Acts not their own. Hopefully there's a bit more to it than that, considering "maps" theoretically already do that.